Polymer electrolyte membrane fuel cell assemblies are relatively low temperature low operating pressure fuel cell assemblies that utilize a catalyzed polymer membrane electrolyte to process air and a hydrogen-rich fuel to produce electricity and water. PEM fuel cells are well suited for use in mobile applications such as automobiles, buses, and the like, because they are relatively compact, light in weight and operate at essentially ambient pressure.
It would be desirable to remove the diffused air and fuel from the water coolant so that the coolant will not be diluted and its cooling capability degraded and degrade its ability to prevent the porous bodies in the cell from drying out. The diffused air and fuel removal operation should be performed while preventing the coolant water from escaping from the coolant flow field.
We have devised a structure and method for effectively removing the diffused air and fuel from the coolant while maintaining a proper back pressure in the coolant flow field and preventing the water coolant from escaping from the coolant flow field.